Characterization of Kilohertz-Ignited Nonthermal He and He/&lt;inline-formula&gt; &lt;tex-math notation="TeX"&gt;${\rm O}_{2}$ &lt;/tex-math&gt;&lt;/inline-formula&gt; Plasma Pencil for Biomedical Applications

Sarani, Abdollah; Nicula, Cosmina; Gonzales, Xavier; Thiyagarajan, M.

doi:10.1109/tps.2014.2313527

Cited by 12 publications

(6 citation statements)

References 55 publications

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“…The existence of ROS in the plasma plume is evidenced by the weak OI emissions at 777 and 844 nm. This finding demonstrates the efficient energy transfer from excited He atoms and metastables to nitrogen and oxygen molecules from the surrounding air . No emissions of excited OH and NO molecules were detected.…”

Section: Resultsmentioning

confidence: 63%

“…Moreover, contrary to corona and dielectric barrier discharge (DBD) that are mostly restricted to flat and thin samples, the APPJs can be successfully applied for treating complex three‐dimensional structures. It has been shown that cold atmospheric plasmas can efficiently inactivate bacteria, cancer cells, fungi, spores, parasites, phages, and viruses . The exact mechanism of cell inactivation by cold plasma jet has not been fully understood, yet.…”

Section: Introductionmentioning

confidence: 99%

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Study of Cold Atmospheric Plasma Jet at the End of Flexible Plastic Tube for Microbial Decontamination

Kostov

Nishime

Machida

et al. 2015

Plasma Processes & Polymers

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Recently, cold atmospheric plasmas have demonstrated very promising antimicrobial activity in vitro and in vivo including selective destruction of tumor cells. However, the size and the rigidity of most plasma systems limit the clinical application for treatments in internal organs or regions with difficult access (e.g., mouth). Here, we report a device that allows ignition of cold He plasma jet at the tip of 1 m long, 3.5 mm diameter, flexible plastic tube. It is connected to a dielectric enclosure where dielectric barrier discharge (DBD) is generated by a low‐frequency AC power supply. A thin wire at floating potential put inside the plastic tube assists the formation of plasma jet at the downstream tube end. The flexible tube can be kept and manipulated by hand without electric shock and thus the plasma jet can be easily directed to a target. Variation of duty cycle of the applied voltage signal allows precise adjustment of the discharge power. The anti‐microbial efficiency of plasma jet system with flexible tube was tested against fungus Candida albicans seeded on agar.

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Section: Resultsmentioning

confidence: 63%

Section: Introductionmentioning

confidence: 99%

Study of Cold Atmospheric Plasma Jet at the End of Flexible Plastic Tube for Microbial Decontamination

Kostov

Nishime

Machida

et al. 2015

Plasma Processes & Polymers

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“…On increasing the voltage over the breakdown, the discharge evolves in the capillary. The arrangement of the syringe needle and the external electrode grounded and at downstream location is characterized by propagation of bullets and the formation of jet that extends to the exterior of the capillary [15], [16], [25]. Other arrangement uses the external electrode over the needle shaft with similar formation of plasma jet [21].…”

Section: B Continuous Operationmentioning

confidence: 99%

“…An external coaxial electrode can also be incorporated. At downstream position, analysis of captured images shows that it reduces the plume length but increases its diameter [15], [16]. Due to small dimensions, diagnostics of such plasmas is a difficult task.…”

Section: Introductionmentioning

confidence: 99%

Characteristics of Needle-Disk Electrodes Atmospheric Pressure Discharges Applied to Modify PET Wettability

Kayama

Silva

Prysiazhnyi

et al. 2017

IEEE Trans. Plasma Sci.

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In the atmospheric pressure discharge with arrangement of a syringe needle, a capillary, and an external disk, it was observed different operation modes according to the relative position of the electrodes. With external electrode over the shaft of the needle, a stable and steady plume is formed from the tip of the needle to the exterior of the capillary. The breakdown is governed by filamentary discharges that evolve randomly on time in the gap between the needle and the capillary. This mechanism changes to bullet-like discharge when the external disk is located off needle. The breakdown generates a large amount of charge that rises quickly and varies with the distance between the electrodes. The mean power is higher than that of the previous case and the plume generated, in interaction with external metallic surface, is more unstable to arc transition. Independently of the operation mode, high electric field at the bevel of the needle plays an important role on the evolution of the plume. The application of the plume to change the wettability properties of the polyethylene terephthalate indicated rapid augment of the hydrophilicy and treated area larger than the plume dimension.

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“…Regarding the effects of additional O 2 on APPJ parameters, the main changes reported in the literature are decrease in jet length, reduction on discharge power and current, and variations in temperatures (rotational and vibrational) [18][19][20][21][22][23][24]. Some works also identified an increment in the applied voltage as a function of the O 2 content, even with the power source configured to apply a fixed voltage to the electrodes, a fact that suggests a change in the load impedance followed by an impedance matching [25,26].…”

Section: Introductionmentioning

confidence: 99%

Effects of O2 Addition on the Discharge Parameters and Production of Reactive Species of a Transferred Atmospheric Pressure Plasma Jet

2021

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The therapeutic effects of atmospheric pressure plasma jets (APPJs) have been associated with the presence of reactive species, mainly the reactive oxygen and nitrogen ones, generated in this kind of plasmas. Due to that, many studies attempting to enhance the production of reactive species in APPJs have been performed. The employment of gas admixtures, usually mixing a noble gas with oxygen (O2) or water vapor, is one of the most common methods to achieve such goal. This work presents a study of how the addition of small amounts of O2 affects the electrical parameters and the production of reactive species in a transferred APPJ produced at the tip of a long and flexible plastic tube. The study was carried out employing helium (He) as the working gas and applying a high voltage (HV) in the form of amplitude-modulated sine waveform (burst mode). With this configuration it was possible to verify that the O2 addition reduces the discharge power and effective current, as a result of late ignition and shorter discharge duration. It was also found that the addition of O2 to a certain content in the gas admixture makes the light emission from oxygen atoms increase, indicating an increment in oxygen related reactive species in the plasma jet. However, at the same time the light emitted from hydroxyl (OH) and nitric oxide (NO) exhibits the opposite behavior, i.e., decrease, indicating a reduction of such species in the APPJ. For these reasons, the addition of O2 to the working gas seems to be useful for increasing the effectiveness of the plasma treatment only when the target modification effect is directly dependent on the content of atomic oxygen.

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Characterization of Kilohertz-Ignited Nonthermal He and He/<inline-formula> <tex-math notation="TeX">${\rm O}_{2}$ </tex-math></inline-formula> Plasma Pencil for Biomedical Applications

Cited by 12 publications

References 55 publications

Study of Cold Atmospheric Plasma Jet at the End of Flexible Plastic Tube for Microbial Decontamination

Study of Cold Atmospheric Plasma Jet at the End of Flexible Plastic Tube for Microbial Decontamination

Characteristics of Needle-Disk Electrodes Atmospheric Pressure Discharges Applied to Modify PET Wettability

Effects of O2 Addition on the Discharge Parameters and Production of Reactive Species of a Transferred Atmospheric Pressure Plasma Jet

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